The third generation partnership project (3GPP) and 3GPP2 are currently considering a long term evolution (LTE) of the universal mobile telecommunication system (UMTS) terrestrial radio access (UTRA). Currently, SC-FDMA is being considered for the evolved UTRA (E-UTRA).
In SC-FDMA, a plurality of orthogonal subcarriers are divided into a plurality of subcarrier blocks, (also known as “resource blocks”). A subcarrier block may be a localized subcarrier block or a distributed subcarrier block. The localized subcarrier block is defined as a set of several consecutive subcarriers and the distributed subcarrier block is defined as a set of several non-consecutive subcarriers. A subcarrier block is a basic scheduling unit for uplink transmissions in an SC-FDMA system. Depending on a data rate or a buffer status, at least one subcarrier block is assigned for a wireless transmit/receive unit (WTRU) for transmission.
MIMO refers to the type of wireless transmission and reception scheme where both a transmitter and a receiver employ more than one antenna. A MIMO system takes advantage of the spatial diversity or spatial multiplexing to improve the signal-to-noise ratio (SNR) and increases throughput.